Idiopathic Orbital Myositis Associated with Graves' Disease

Abstract

A 52-year-old man was referred to our clinic. One week before his visit, he had complained of left eye pain and double vision. His clinical features were exacerbated. Despite the acute onset, which is atypical of thyroid eye disease (TED), TED was suspected due to the patient's history of Graves' disease (GD). After conducting clinical examinations and orbital magnetic resonance imaging, the patient was diagnosed with idiopathic orbital myositis (IOM), and intravenous glucocorticoid therapy was administered. After treatment, the patient's clinical manifestations dramatically improved. This is a rare case in that the history of GD made it difficult to differentiate IOM from TED.

Secondary myopathy due to systemic diseases

“…Graves’ disease may manifest in the skeletal muscle as mild and usually painless proximal weakness or as idiopathic ocular myositis . Myositis may respond favorable to thiamazole without adding steroids .…”

A Case of Euthyroid Graves’ Ophthalmopathy in a Patient Sero-Negative for TSH Receptor Autoantibody

“…The clinical features of the idiopathic inflammation of the extraocular muscle also known as idiopathic orbital myositis are acute and severe pain of the eyes, proptosis, eyelid swelling, and erythema, and conjunctival redness and chemosis [ 2 , 13 ]. MRI images of the disease reportedly show unilateral enlargement of the extraocular muscle (especially superior rectus or lateral rectus muscles) that involves the tendons with vague contour of the muscle [ 3 , 13 ].…”

“…With these findings, the differential diagnosis of this case were (1) euthyroid Graves' ophthalmopathy with a slight increase in TSAb alone or (2) idiopathic inflammation of the extraocular muscle [ 2 ]. Based on the insidious onset, absence of ocular pain, predominance of inferior rectus muscle swelling, and apparent muscular swelling with minimally swollen tendons [ 1 – 3 ], we diagnosed this case as TRAb-negative euthyroid Graves' ophthalmopathy.…”

Non-traumatic and non-drug-induced rhabdomyolysis

“…Hyperthyroidism may present as indolent proximal weakness, idiopathic ocular myositis or polymyositis [88,89]. Painless thyroiditis is characterized by transient thyrotoxicosis lasting 2-4 weeks, followed by hypothyroidism for 1-3 months, and then resolution.…”